The present invention relates to a channel plate adapter for an open-end rotor spinning arrangement.
Open-end rotor spinning arrangements are commonly equipped with an exchangeable channel plate adapter in the area of their fiber channel plate, as is known and extensively described, for example, in German Patent Publication DE 43 34 485 A1.
During the spinning operation of such open-end rotor spinning arrangements, a spinning rotor turns at a high rate of revolutions in a rotor housing, to which a suction force is applied to create an underpressure in the housing.
In the course of this operation, the rotor housing is closed by means of a pivotably arranged cover, into which a sliver opening device of the spinning arrangement is additionally integrated. More specifically, a lip seal is arranged in an annular groove of a so-called fiber channel plate and rests against the front of the rotor housing to effect the closure of the housing.
In such case, the fiber channel plate is either an integral component of the cover, or is releasably fixed on the cover. Additionally, a channel plate adapter is exchangeably arranged in a centered receiver of the fiber channel plate and forms a portion of a fiber guide channel, as well as carrying a yarn withdrawal nozzle in a centered through-bore.
In order to assure an optimum yarn feed, as well as a good yarn withdrawal, the channel plate adapters are each matched to a defined spinning rotor shape, or size. For this reason the channel plate adapter is also often exchanged in circumstances in which the spinning rotor may be changed, for example, in the case of a batch change.
Various embodiments are known for accomplishing the fastening of such exchangeable channel plate adapters. For example, a channel plate adapter is described in German Patent Publication DE 43 34 485 A1, wherein the channel plate adapter can be fixed in place in an airtight manner in the receiver of the fiber channel plate by means of screws extending through the back of the receiver. However, this manner of fastening requires the use of a tool.
In contrast thereto, channel plate adapters as described in German Patent Publication DE 197 29 192 A1 can be exchanged without tools. These known channel plate adapters are equipped with a central extension with lateral fixation elements, as viewed in the installation direction.
In particular, the channel plate adapter in this arrangement is uniformly fixed in place in the receiver of the fiber channel plate by means of the action of these fixation elements arranged approximately in the area of the center axis of the channel plate adapter by means of appropriate arresting means. Thus, false air is prevented from entering the rotor housing.
Channel adapter plates of this type have a central through-bore, in which is arranged a yarn withdrawal nozzle which, in general practice, is also exchangeable. Different embodiments also exist for accomplishing the releasable fastening of such yarn withdrawal nozzles.
German Patent Publication DE 39 40 046 A1, for example, describes a yarn withdrawal nozzle having an orifice funnel made of a ceramic material, which is fixed in place in a steel orifice support, preferably by adhesive. The orifice support itself has an outer thread, which can be screwed into a corresponding inner thread in the area of the central through-bore of the channel plate adapter.
Another form of releasable yarn-withdrawal nozzle as described in German Patent Publication DE 195 02 917 C2, has a ceramic orifice funnel with a ferromagnetic contact surface on its back. This ferromagnetic contact surface acts together with permanent magnets fixedly embedded into the channel plate adapter.
It has also been proposed in German Patent Publication DE 37 29 425 A1 to fix the yarn withdrawal nozzle exchangeably on a fiber channel plate with the aid of special additional clip-on closures. In this case, the clip-on closures are either fastened on the fiber channel plate to snap into corresponding shoulders at the yarn withdrawal nozzle, or the clip-on closures are a component of the yarn withdrawal nozzle which act together with corresponding installations at the fiber channel plate.
The above described installations for the interchangeable fixing in place of a yarn withdrawal nozzle each have various disadvantages. The arrangement known from German Patent Publication DE 37 29 425 A1, for example, is somewhat elaborate because of its various individual parts whereby the production costs of such channel plate adapters are relatively high.
Another open-end spinning arrangement is known from German Patent Publication DE 196 03 730 A1 wherein the channel plate adapter is made of plastic in a cost-effective manner and is exchangeably arranged in a receiver of the fiber channel plate. Here, a fiber guide channel produced from a wear-resistant material is molded into the plastic channel plate adapter.